Authentication - lesson 2 | HackIndia Skills

Authentication - lesson 2 | HackIndia Skills | HackIndia

Example

Node example

This example uses bcrypt in an Express-style app. The same idea applies in Next.js, FastAPI, Django, Rails, or Laravel.

Install with npm install bcrypt. If bcrypt gives install trouble on your laptop, bcryptjs can work for learning, but use bcrypt or Argon2 in serious projects.

import bcrypt from "bcrypt";

const SALT_ROUNDS = 12;

export async function createUser(email, password) {
  const passwordHash = await bcrypt.hash(password, SALT_ROUNDS);

  const user = await db.user.create({
    data: {
      email,
      passwordHash
    }
  });

  return { id: user.id, email: user.email };
}

export async function loginUser(email, password) {
  const user = await db.user.findUnique({ where: { email } });
  if (!user) return null;

  const ok = await bcrypt.compare(password, user.passwordHash);
  if (!ok) return null;

  return { id: user.id, email: user.email };
}

Hash passwords correctly

One rule

Why slow hashes

Do not do this

Signup flow

Node example

What to store

AI check

Do this now

Quick check